CN111971745B - Magnetic recording medium - Google Patents
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- CN111971745B CN111971745B CN201880091890.8A CN201880091890A CN111971745B CN 111971745 B CN111971745 B CN 111971745B CN 201880091890 A CN201880091890 A CN 201880091890A CN 111971745 B CN111971745 B CN 111971745B
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Images
Classifications
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- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/62—Record carriers characterised by the selection of the material
- G11B5/64—Record carriers characterised by the selection of the material comprising only the magnetic material without bonding agent
- G11B5/66—Record carriers characterised by the selection of the material comprising only the magnetic material without bonding agent the record carriers consisting of several layers
- G11B5/672—Record carriers characterised by the selection of the material comprising only the magnetic material without bonding agent the record carriers consisting of several layers having different compositions in a plurality of magnetic layers, e.g. layer compositions having differing elemental components or differing proportions of elements
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/62—Record carriers characterised by the selection of the material
- G11B5/64—Record carriers characterised by the selection of the material comprising only the magnetic material without bonding agent
- G11B5/65—Record carriers characterised by the selection of the material comprising only the magnetic material without bonding agent characterised by its composition
- G11B5/658—Record carriers characterised by the selection of the material comprising only the magnetic material without bonding agent characterised by its composition containing oxygen, e.g. molecular oxygen or magnetic oxide
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/84—Processes or apparatus specially adapted for manufacturing record carriers
Abstract
The perpendicular magnetic recording medium of the present invention has a granular layer (2) and a cap layer (3) as layers constituting at least a part of a recording layer (1), the granular layer (2) containing a metal oxide as a nonmagnetic material and a magnetic material dispersed in the nonmagnetic material, the cap layer (3) being formed on the granular layer (2) and containing no metal oxide, and an oxide phase of a boundary portion with the cap layer of the granular layer immediately below the cap layer (3) containing at least one selected from the group consisting of Zn, W, Mn, Fe and Mo.
Description
Technical Field
The present invention relates to a perpendicular magnetic recording medium having a granular layer (granular layer) in which a magnetic body is dispersed in a nonmagnetic body containing a metal oxide, and a cap layer (cap layer) formed on the granular layer and not containing a metal oxide as layers constituting at least a part of a recording layer, and in particular, proposes a technique capable of contributing to improvement of Switching Field Distribution (SFD) required for high-density recording.
Background
In hard disk drives, a perpendicular magnetic recording system for recording magnetism in a direction perpendicular to a recording surface has been put to practical use, and this system is widely used because it can realize high-density recording as compared with a conventional in-plane magnetic recording system.
A perpendicular magnetic recording medium is generally configured by laminating a soft magnetic layer, an intermediate layer, a recording layer, and the like in this order on a substrate of aluminum, glass, or the like. Among them, the recording layer has a granular layer in the lower part, and the granular layer is formed by dispersing SiO in a magnetic body such as Co-Pt alloy containing Co as the main component2And the like. Thus, in the recording layer, the above-mentioned metal oxide as a nonmagnetic material is precipitated at grain boundaries of magnetic particles of a magnetic material such as a Co alloy oriented in the vertical direction, and the magnetic interaction between the magnetic particles is reduced, thereby improving the noise characteristics caused by the reduction of the magnetic interactionHigh and realizes high recording density. As a technique related to this, there is a technique described in patent document 1.
Each layer of such a magnetic recording medium is generally formed by sputtering using a magnetron sputtering apparatus using a sputtering target having a predetermined composition corresponding to the layer, as described in patent document 2, for example.
Documents of the prior art
Patent document
Patent document 1: japanese patent No. 4021435
Patent document 2: japanese patent No. 5960287
Disclosure of Invention
Problems to be solved by the invention
In the recording layer of the perpendicular magnetic recording medium as described above, the recording layer usually has a cap layer formed on the granular layer, not including the metal oxide, and mainly composed of a magnetic material, in addition to the granular layer. Accordingly, the magnetic particle layer is made low in noise by utilizing the particle separability of the magnetic particle layer in which the magnetic particles are magnetically separated by the metal oxide, and the capping layer in which the interaction between the magnetic particles is left due to the absence of the metal oxide provides an appropriate interaction between the magnetic particles to the magnetic particle layer, thereby ensuring the ease of writing in the medium, the reduction in SFD, the thermal stability, and the like.
When a cap layer is formed on the granular layer by sputtering or the like in order to form the recording layer of such a perpendicular magnetic recording medium, a thin film of the cap layer selectively grows in a portion of the granular layer where the metal oxide does not exist due to a difference in wettability between the metal oxide in the granular layer and the metal of the cap layer. As a result, the initial growth of the thin film of the cap layer becomes nonuniform following the morphology of the particle layer including the metal oxide, and therefore, there is a problem as follows: even if a cap layer of a prescribed thickness is formed, the Switching Field Distribution (SFD) is not improved. On the other hand, if a thick cap layer is formed, although the SFD is improved, the distance between the magnetic head and the center of the medium becomes large, the resolution is lowered, and the exchange coupling between the magnetic particles becomes large due to the thick cap layer, the cluster size becomes large, and the recording density cannot be increased.
The present invention has been made to solve the above-mentioned problems of the conventional perpendicular magnetic recording medium, and an object of the present invention is to provide a perpendicular magnetic recording medium in which a cap layer is uniformly laminated on a granular layer of a recording layer, thereby efficiently improving the Switching Field Distribution (SFD).
Means for solving the problems
As a result of intensive studies, the inventors have found that, in a recording layer, a boundary portion between a granular layer located directly below a cap layer and the cap layer contains a predetermined metal oxide, and that the cap layer is also laminated on a nonmagnetic portion of the granular layer from the initial stage of growth thereof, similarly to a magnetic body portion of the granular layer, due to good wettability of the metal oxide with the cap layer containing much Co or the like, and as a result, a uniform cap layer is formed on the granular layer. In addition, in view of efficiently separating the magnetic particles, in the case where an oxide of a predetermined metal is used as the metal oxide at the boundary portion of the granular layer, the magnetic separability required for the magnetic particles in the granular layer can be achieved.
In the perpendicular magnetic recording medium of the present invention, the granular layer contains a metal oxide as a nonmagnetic material and a magnetic material dispersed in the nonmagnetic material, and the cap layer is formed on the granular layer and does not contain a metal oxide, and the oxide phase of the boundary portion with the cap layer of the granular layer immediately below the cap layer contains at least one selected from the group consisting of Zn, W, Mn, Fe, and Mo as a layer constituting at least a part of the recording layer.
In the perpendicular magnetic recording medium of the present invention, it is preferable that the oxide phase of the boundary portion of the granular layer contains at least Zn among the metals described above.
In the perpendicular magnetic recording medium of the present invention, the oxide phase of the boundary portion of the granular layer may further contain at least one of B and Si, and the oxide phase of the boundary portion of the granular layer may further contain Ti.
For the perpendicular magnetic recording medium of the present invention, it is preferable that the remaining portion of the granular layer other than the boundary portion has a layer containing no Zn.
In this case, it is more preferable that the remaining part of the particle layer contains an oxide of at least one element selected from the group consisting of Si, B, and Ti as an oxide phase, and a total content of the oxides of the oxide phase in the remaining part is 20 vol.% to 50 vol.%.
In the perpendicular magnetic recording medium of the present invention, it is preferable that the oxide phase at the boundary portion of the granular layer contains Zn, and the content of Zn in the oxide phase is 3 at% or more.
In the perpendicular magnetic recording medium of the present invention, it is preferable that the boundary portion has a thickness of 3% to 50% of the thickness of the entire granular layer in the stacking direction of the recording layers.
Here, the magnetic particles of the entire granular layer including the boundary portion may contain Co as a main magnetic material and at least one metal selected from the group consisting of Pt, Ru, and Cr. The magnetic body may have a so-called ECL (Exchange Coupling Layer) which is cut off in the vertical direction by a nonmagnetic Layer mainly composed of Co or Ru.
The cap layer may contain at least one metal selected from the group consisting of Cr, Pt, and B, and may mainly contain Co.
In the perpendicular magnetic recording medium of the present invention, it is preferable that the cap layer has a thickness of 1nm to 3nm in a direction in which the recording layers are stacked.
Effects of the invention
According to the perpendicular magnetic recording medium of the present invention, since the oxide phase of the grain layer immediately below the cap layer at the boundary portion with the cap layer contains the above-mentioned metal, the cap layer also grows on the nonmagnetic portion of the grain layer containing the oxide phase of the metal from the initial stage of the growth of the cap layer, and therefore, the cap layer is uniformly laminated on the grain layer, whereby the Switching Field Distribution (SFD) can be improved.
Drawings
Fig. 1 is a cross-sectional view schematically showing a recording layer of a perpendicular magnetic recording medium according to an embodiment of the present invention, the cross-sectional view being taken along a stacking direction of the recording layer.
Fig. 2 is a cross-sectional view schematically showing a recording layer of a conventional perpendicular magnetic recording medium, the cross-sectional view being taken along a stacking direction of the recording layer.
Fig. 3 is a graph showing the change in Ra accompanying the increase in the film thickness tc of the cap layer during sputtering in test example 1 of the example.
FIG. 4 is a graph showing the change in-Hn accompanying the increase in the film thickness tc of the cap layer during sputtering in test example 1 of the present example.
FIG. 5 shows the Zn content and the Ra of the cap layer in test example 3 of the examples being less than
A graph of the relationship between the film thickness of the cap layer (1).
FIG. 6 is a graph showing the relationship between the Zn content and the film thickness of the cap layer in which-Hn is positive in test example 3 of the example.
Detailed Description
Hereinafter, embodiments of the present invention will be described in detail.
A perpendicular magnetic recording medium according to an embodiment of the present invention has a recording layer, and as shown in fig. 1, the recording layer 1 has a granular layer 2 and a cap layer 3 as layers constituting at least a part of the recording layer 1, the granular layer 2 contains a metal oxide as a nonmagnetic material and a magnetic material dispersed in the nonmagnetic material, and the cap layer 3 is formed on the granular layer 2 and does not contain a metal oxide. Therefore, in the recording layer 1 of the present embodiment, the granular layer 2 includes the oxide phase 4a made of a nonmagnetic material and the metal phase 4b made of a magnetic material, while the cap layer 3 includes no metal oxide and is made of only a predetermined metal.
In the perpendicular magnetic recording medium, for example, a substrate, a soft magnetic layer, an intermediate layer, and the recording layer 1 may be stacked in this order, and the portions other than the recording layer 1 may be the same as those in the conventional art, and therefore, the description thereof will be omitted. The recording layer 1 of the present embodiment includes the granular layer 2 and the cap layer 3, but may include an Onset (initial) layer, an ECL layer, and the like, which are nonmagnetic or magnetic with a small magnetic moment.
(cover layer)
The cap layer 3 is made of only a metal of a magnetic material without containing a metal oxide, and specific examples of such a metal include: mainly Co, and further comprises at least one metal selected from the group consisting of Cr, Pt and B.
The metal constituting the cap layer 3 is typically mainly composed of Co and Pt, and may contain one or more metals selected from the group consisting of Cr and B as necessary. The cap layer 3 is usually an alloy mainly composed of CoCrPtB.
In the present embodiment, as described below, since the cap layer 3 can be uniformly laminated on the granular layer 2 from the initial stage of film formation when the cap layer 3 is formed, the Switching Field Distribution (SFD) can be efficiently improved without increasing the thickness tc of the cap layer 3 more than necessary. The thickness tc of the cover layer 3 may be preferably set to 3% to 30% as a percentage of the thickness tg of the entire particle layer 2. Specifically, the thickness tc of the cap layer 3 is preferably 0.5nm to 3 nm.
(particle layer)
The granular layer 2 includes an oxide phase 4a made of a metal oxide that is a non-magnetic body and a metal phase 4b made of a magnetic body as a whole, but it is important that the granular layer 2 is composed of at least two layers including a boundary portion 2a located immediately below the cap layer 3 and a remaining portion 2b located below the boundary portion 2a, other than the boundary portion 2a, as shown in fig. 1, when viewed in the stacking direction of the recording layer 1. The boundary portion 2a and the remaining portion 2b are different in metal oxide constituting the oxide phase 4a thereof.
Specifically, the oxide phase 4a of the boundary portion 2a contains at least one selected from the group consisting of Zn, W, Mn, Fe, and Mo, and preferably contains Zn. Here, the oxide contained in the boundary portion 2a is mainly ZnO.
Accordingly, when the cap layer 3 is formed on the granular layer 2 by sputtering, the metal constituting the cap layer 3 not containing a metal oxide and ZnO at the boundary portion 2a of the granular layer 2 exhibit good wettability, and thus the metal constituting the cap layer 3 can be uniformly laminated on the entire oxide phase 4a of the granular layer 2 including the boundary portion 2a from the initial stage of growth of the cap layer 3. This effectively exerts the function of the cap layer 3, and improves the Switching Field Distribution (SFD). Further, ZnO can effectively separate the magnetic particles of the metal phase 4b of the granular layer 2, and therefore, even in the boundary portion 2a of the granular layer 2, the required magnetic separability can be secured substantially in the same manner as in the remaining portion 2 b.
In the conventional perpendicular magnetic recording medium, as shown in fig. 2, since the oxide phase 14a of the granular layer 12 is composed of an oxide of a metal other than the above-described metal in the entire stacking direction, when the cap layer 13 is formed, the metal of the cap layer 13 is selectively stacked on the metal phase 14b of the granular layer 12 in which the metal oxide is not present in the initial stage of growth thereof. That is, as schematically shown in fig. 2, a portion where the metal of the cap layer 13 cannot be stacked is generated in the lower portion of the cap layer 13 near the granular layer 12 due to excellent crystallinity, so-called epitaxial growth. Thus, even if the cap layer 13 is formed to have a predetermined thickness, improvement of the Switching Field Distribution (SFD) cannot be achieved. Further, it is considered that the Switching Field Distribution (SFD) can be prevented from being improved by making the cover layer 13 sufficiently thick, but in this case, the distance between the head and the center of the medium becomes large, and the resolution is lowered, and there are other problems as follows: the exchange coupling between the magnetic particles becomes large due to the thick cap layer 13, the cluster size becomes large, and the recording density cannot be increased.
In the embodiment of the present invention shown in fig. 1, the oxide phase of the boundary portion 2a contains Zn, W, Mn, Fe and/or Mo which are easily wetted with the cap layer 3, and therefore such conventional problems can be effectively solved.
When Zn is contained in the boundary portion 2a of the particle layer 2, the Zn content is preferably 3 at% or more. When the Zn content in the boundary portion 2a is less than 3 at%, the wettability is not expected to be improved, and the cap layer is not easily epitaxially grown on the oxide phase, and when the Zn content in the boundary portion 2a exceeds 25 at% or more, a large amount of Zn enters the metal phase, and thus, there is a concern that the magnetic anisotropy and crystallinity are reduced.
In order to improve wettability, the oxide phase at the boundary portion 2a of the particle layer 2 is more preferably a metal oxide containing at least one selected from the group consisting of Zn, W, Mn, Fe, and Mo, B and Si for improving amorphousness (amophorus), and Ti for improving separability. That is, the oxide phase of the boundary portion 2a of the granular layer 2 may contain only at least one selected from the group consisting of Zn, W, Mn, Fe, and Mo, and may contain at least one of B and Si, and/or Ti in addition to these.
The ratio (tb/tg) of the thickness tb of the boundary portion 2a of the particle layer 2 to the thickness tg of the entire particle layer 2 as viewed in the stacking direction of the recording layers is preferably 3% to 50% in percentage. If the ratio (tb/tg) of the thickness tb of the boundary portion 2a to the entire thickness tg is less than 3%, the effect of uniform film formation of the cap layer 3 by the ZnO in the boundary portion 2a may not be sufficiently obtained. The ratio (tb/tg) of the thickness tb of the boundary portion 2a to the entire thickness tg of the particle layer 2 is further preferably set to 3% to 30%.
On the other hand, the oxide phase of the remaining portion 2b of the particle layer 2, which does not largely affect the uniform film formation of the cap layer 3, may contain Zn similarly to the boundary portion 2a, but preferably does not contain Zn. Further, the remaining portion 2b of the particle layer 2 is preferably a layer not containing ZnO but not containing Zn. This is because: that is, in the case where the remaining portion 2b of the granular layer 2 contains Zn, there is a concern that the magnetic anisotropy Ku may decrease.
The remaining part 2B of the granular layer 2 may contain, as an oxide phase, an oxide of at least one element selected from the group consisting of Si, B, and Ti, instead of the predetermined metal oxide such as ZnO as described above. The total content of the oxides in the remaining portion 2b including the oxides other than the oxides is preferably 20 vol.% to 50 vol.%. When the total content of the oxides in the remainder 2b is less than 20 vol.%, the separation of the metal phase is insufficient, and the cluster size may become large, and when it exceeds 50 vol.%, the proportion of the metal phase is small, and sufficient Ku and magnetic anisotropy cannot be obtained, and there is a possibility that the thermal stability and the reproduction signal intensity are insufficient. The volume fraction of the oxide in the film was determined by TEM observation.
The metal phase 4b, which is a magnetic body of the granular layer 2, is mainly made of Co, and further contains at least one metal selected from the group consisting of Pt, Ru, and Cr.
Examples
Next, the perpendicular magnetic recording medium of the present invention is manufactured in a trial manner, and the performance thereof is evaluated, and therefore, the following description is given. However, the description herein is for illustrative purposes only and is not intended to be limiting.
(test example 1)
As example 1-1, a sample was obtained by forming films of Cr-Ti (6nm), Ni-W (5nm) and Ru (20nm) in this order on a glass substrate by a magnetron sputtering apparatus (C-3010 sputtering system manufactured by CANON ANELVA), and Co-Pt-SiO was formed on the sample2The (10nm) film was used as a lower granular layer (the remaining part of the granular layer), each magnetic film having a film thickness of 3nm was formed as an upper granular layer (the boundary part between the granular layer and the cap layer) on the lower granular layer by sputtering 300W in an atmosphere of Ar at 5.0Pa using a sputtering target containing Co-Pt-ZnO, and each layer was formed by forming a Co-Cr-Pt-B (0 to 8nm) film as a cap layer on the upper granular layer. In example 1-1, the oxide of the upper particle layer contains ZnO.
Further, as examples 1-2 to 1-5, the oxide of the upper particle layer contained WO3、MnO、Fe2O3、MoO3Otherwise, the same film as in example 1 was formed.
In comparative example 1, the oxide phase of the upper particle layer contained SiO2Except for this, each layer was formed in the same manner as in example 1.
In examples 1-1 to 1-5 and comparative example 1, the roughness (Ra) and the inversion-starting magnetic field (-Hn) were measured with respect to the film thickness of the cap layer. A comparison thereof is graphically shown in fig. 3 and 4. In FIGS. 3 and 4, SiO2Refer to comparative example 1, ZnO refers toExample 1-1, WO3Refer to examples 1-2, MnO refers to examples 1-3, Fe2O3Refer to examples 1-4, MoO3Refer to examples 1-5.
In examples 1-1 to 1-5 and comparative example 1, the lower granular layer was 67 Co-23 Pt-10 SiO2(mol%) and the capping layer is 60 Co-10 Cr-15 Pt-5B (mol%).
In example 1-1, the upper particle layer was 62 Co-21 Pt-17 ZnO (mol%) (ZnO ═ 30 vol.%), and in comparative example 1, the upper particle layer was 67 Co-22 Pt-10 SiO2(mol％)(SiO230 vol.%). As for the upper particle layer, 70 Co-23 Pt-7 WO in example 1-23(mol％)(WO330 vol.%), 61 Co-20 Pt-19 MnO (mol.%) in examples 1-3 (30 vol.%), and 68 Co-23 Pt-10 Fe in examples 1-42O3(mol％)(Fe2O330 vol.%), 62 Co-21 Pt-18 MoO in examples 1-53(mol％)(MoO3＝30vol.％)。
The roughness (Ra) was measured by an Atomic Force Microscope (AFM) manufactured by SII, and the reversal initiation magnetic field (-Hn) was measured by a Vibrating Sample Magnetometer (VSM) manufactured by Yukawa.
As shown in fig. 3: and is set to SiO2In comparative example 1, in examples 1-1 to 1-5, a sufficient decrease in Ra was observed even when the film thickness (tc) of the cap layer was small, and thus the wettability of the upper Co-based cap layer with the Zn oxide was good. Further, as can be seen from fig. 4: in examples 1-1 to 1-5, and is SiO2In comparison with comparative example 1, the SFD effect of the cap layer was obtained by making d (-Hn)/dtc positive in the range where the cap layer was thinner.
(test example 2)
As reference examples, 67 Co-22 Pt-10 SiO as a sputtering target not containing Zn was used2(mol％)(SiO230 vol.%), 62 Co-21 Pt-17 ZnO (mol%) (ZnO 30 vol.%), which is a sputtering target containing Zn, and the same procedure as in test example 1 was repeatedThe sample in which the single particle layer of 13nm was formed after the formation of the Ru film was prepared, and the magnetic anisotropy Ku was measured.
The magnetic anisotropy (Ku) was measured by a magnetic torque meter (TRQ) manufactured by kawa corporation.
The oxide of the granular layer is SiO2In the case of (2), the Ku value is 6.16X 106erg/cc, in contrast, when ZnO is used as the oxide of the particle layer, the Ku value is 5.04X 106erg/cc. Thus, it can be seen that: when a sputtering target containing Zn is used, Ku becomes low. Therefore, since a sputtering target having a high Ku composition is often used for the lower granular layer, it can be said that a layer containing no Zn is preferably present in the lower granular layer.
(test example 3)
As examples 3-1 to 3-22, Co-Pt-ZnO and Co-Pt-SiO were used2－ZnO、Co－Pt－B2O3－ZnO、Co－Pt－TiO2A plurality of test pieces were produced by using a ZnO sputtering target in which the Zn content was varied. The composition of each sputtering target is shown in table 1 for reference.
[ Table 1]
Using the respective test pieces, a magnetic film was formed in the same manner as in test example 1, and the roughness (Ra) with respect to the film thickness of the cap layer and the inversion-starting magnetic field (-Hn) were measured. The above-described test article is used for forming an upper granular layer of a magnetic film. The Zn content and the Ra of the cover layer are less than
The relationship between the film thickness of the cap layer (2) and the film thickness of the cap layer having a positive Zn content is shown in FIG. 5, and the relationship between the film thickness of the cap layer having a positive-Hn content and the film thickness of the cap layer having a positive-Hn content is shown in FIG. 6.
As can be seen from fig. 5: in particular, in examples 3-5 to 3-8, 3-12 to 3-15, and 3-19 to 3-22 in which Zn in the upper particle layer was 3 at% or more, a sufficient decrease in Ra was observed even when the cap layer was thin, and thus the wettability of the upper Co-based cap layer and the Zn oxide was further improved. Further, as can be seen from fig. 6: in particular, in examples 3-5 to 3-8, 3-12 to 3-15 and 3-19 to 3-22 in which Zn in the upper particle layer is 3 at% or more, the film thickness of the positive cap layer of d (-Hn)/dtc is considerably thin, and thus SFD is further improved by adding Zn to the thin cap layer.
Description of the reference numerals
1: a recording layer; 2: a particulate layer; 2 a: a boundary portion; 2 b: the remainder; 3: a cap layer; 4 a: a metal phase; 4 b: an oxide phase; tg: the thickness of the particle layer as a whole; tb: a thickness of the boundary portion; tc: the thickness of the cap layer.
Claims (9)
1. A perpendicular magnetic recording medium having a granular layer and a cap layer as layers constituting at least a part of a recording layer, the granular layer containing a metal oxide as a nonmagnetic material and a magnetic material dispersed in the nonmagnetic material, the cap layer being formed on the granular layer and containing no metal oxide and being composed of only a metal of the magnetic material, the metal phase of the granular layer containing Co, the oxide phase of a boundary portion with the cap layer of the granular layer immediately below the cap layer containing at least one selected from the group consisting of Zn, W, Mn, Fe and Mo, the oxide phase of the boundary portion of the granular layer containing Zn, the oxide phase having a Zn content of 3 at% or more.
2. The perpendicular magnetic recording medium according to claim 1,
the oxide phase of the boundary portion of the particle layer further contains at least one of B and Si.
3. The perpendicular magnetic recording medium according to claim 1 or 2,
the oxide phase of the boundary portion of the particle layer further contains Ti.
4. The perpendicular magnetic recording medium according to claim 1 or 2,
the remaining portion of the particle layer other than the boundary portion has a layer not containing Zn.
5. The perpendicular magnetic recording medium according to claim 4,
the remaining part of the particle layer contains an oxide of at least one element selected from the group consisting of Si, B, and Ti as an oxide phase, and the total content of the oxides of the oxide phase in the remaining part is 20 vol.% to 50 vol.%.
6. The perpendicular magnetic recording medium according to claim 1 or 2,
the boundary portion has a thickness of 3% to 50% of the thickness of the entire granular layer in the stacking direction of the recording layers.
7. The perpendicular magnetic recording medium according to claim 1 or 2,
the entire particle layer including the boundary portion contains at least one metal selected from the group consisting of Co, Pt, Ru, and Cr as a metal phase.
8. The perpendicular magnetic recording medium according to claim 1 or 2,
the capping layer contains at least one metal selected from the group consisting of Co, Cr, Pt and B.
9. The perpendicular magnetic recording medium according to claim 1 or 2,
the cap layer has a thickness of 1nm to 3nm in the stacking direction of the recording layers.
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| Application Number | Priority Date | Filing Date | Title |
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| JP2018-063229 | 2018-03-28 | ||
| JP2018063229 | 2018-03-28 | ||
| PCT/JP2018/035132 WO2019187226A1 (en) | 2018-03-28 | 2018-09-21 | Perpendicular magnetic recording medium |
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| CN111971745A CN111971745A (en) | 2020-11-20 |
| CN111971745B true CN111971745B (en) | 2022-05-10 |
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| CN (1) | CN111971745B (en) |
| SG (1) | SG11202009585QA (en) |
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Also Published As
| Publication number | Publication date |
|---|---|
| TW201942900A (en) | 2019-11-01 |
| SG11202009585QA (en) | 2020-10-29 |
| JPWO2019187226A1 (en) | 2021-05-27 |
| JP7116782B2 (en) | 2022-08-10 |
| CN111971745A (en) | 2020-11-20 |
| TWI713985B (en) | 2020-12-21 |
| WO2019187226A1 (en) | 2019-10-03 |
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